in your opinion, what’s the best qt5 image viewer that supports color management? Unfortunately Lximage form Lxqt does not support color management.
Maybe Nomacs? XnView is also qt I believe but it is not open source and maybe a bit too heavy.

I think qimgv is the first program that I compiled successfuly
Appears to be really very lightweight. Did not test color management capabilites yet though
However, Gwenview looks very nince, too, and does not need a lot of KDE libraries